Remove suggestion to use -f in git push

Co-authored-by: Pierre R. Mai <pmai@pmsf.de>
Signed-off-by: Pierre R. Mai <pmai@pmsf.de>

Author: engelben

doc/howtocontribute.rst

@@ -65,7 +65,7 @@ The DCO requires a sign-off message in the following format appear on each commi
 
   Signed-off-by: Firstname Lastname <email@address.com>
 
-The DCO text can either be manually added to your commit body, or you can add either -s or --signoff to your usual Git commit commands. If you forget to add the sign-off you can also amend a previous commit with the sign-off by running git commit --amend -s. If you’ve pushed your changes to GitHub already you’ll need to force push your branch after this with git push -f.
+The DCO text can either be manually added to your commit body, or you can add either ``-s`` or ``--signoff`` to your usual Git commit commands. If you forget to add the sign-off you can also amend a previous commit with the sign-off by running ``git commit --amend -s``. If you’ve pushed your changes to GitHub already you’ll need to force push your branch after this with ``git push --force-with-lease``.
 
 
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